Why Climate Change Wasn’t Behind Paris’s Record-High Temperature

It’s summer, temperatures are hot － sometimes record hot － and as usual, climate alarmism reaches record highs as climate activists have a field day with fearmongering rather than with facts and data.

Every week, various weather events end up getting caught in the spokes of the wheel of climate; it’s an endless cycle. Rinse, wash, repeat.

This time, it’s the [second] European heatwave this summer.

A Bit of Historical Perspective

While countries like the Netherlands, Germany, and Belgium have recorded their hottest temperatures on record this week, Paris’s record high of 108.7°F (42.6°C) on Thursday, July 25, made international headlines and consequently sparked climate insanity.¹

The graph below (Figure 1) shows the maximum temperature in Paris, France for each year since 1900.² As indicated by the red trendline, there has been a noticeable increase in the annual maximum temperature in Paris over the long run, however, the trend is not alarming.

Paris’s previous hottest temperature record stood for nearly 72 years.³

On July 28, 1947, the city reached 104.7°F (40.4°C).³ Paris’s high of 108.7°F (42.6°C) on Thursday broke the old record by 4°F (2.2°C), an incredible feat by any stretch of the imagination.

To break an all-time temperature record by 4°F in summer, let alone tie it, is extremely difficult to do, even with global warming.

The 1947 heatwave was an incredible one in Europe and it’s forever stitched in the memories of elders.

In Paris, the heatwave lasted for 12 days (July 22 through August 2) with highs consistently at or above 90°F (32.2°C).³ Two days were at or above 100°F (37.8°C), and four were at or above 95°F (35°C).³

What really stuck out to me when comparing maximum temperatures this summer with 1947 is that maximum temperatures seem to trace those of 1947 (Figure 2). It’s quite interesting and odd.

Is Climate Change to Blame?

Like many scientists, I agree that climate change － both natural fluctuations or man-made forcings like land use and urbanization － should cause weather patterns and the intensity and/or frequency of extreme weather or weather-related events to change.

It’s indeed possible that the warmer atmosphere today, as compared to the 1980s, may have made this heatwave slightly more intense. However, nobody knows for sure because heatwaves have always occurred; some are just worse than others. It’s summer.

While this heatwave is the latest poster child for the planet’s “ecological breakdown,” there is a natural explanation for this heatwave, as with all other weather events.

There has been a persistent weather pattern that’s causing this bake-fest. A large area of high pressure is stationed over Europe and an area of low pressure is situated off of the coast of Ireland.⁴

The wind flow around these pressure centers is drawing in air from the south, which is blowing hot Saharan air into Europe (Figure 3).⁴

This natural process occurs with or without 415 parts per million (ppm) or 0.04% of carbon dioxide in the atmosphere.

The air over France at the time of Paris’s record-high temperature was relatively dry (Figure 4), and as any weather hobbyist or meteorologist should know, dry air heats up faster than saturated air.

Had the dew points (and thus relative humidity) been higher Thursday afternoon, the record-high temp may not have been set!

It’s also worth pointing out that Paris, like any other large city, is a massive Urban Heat Island (UHI).

When land is developed, urban infrastructure takes the place of land previously covered with vegetation like grass, and especially forests.⁵ This urbanized land limits the amount of plant transpiration (evaporation that cools plant leaves and air temperatures).⁵

Buildings like factories, skyscrapers, houses, and shops, not to mention automobiles and dark infrastructure like roads and black roofs absorb and retain more heat than grassy surfaces or forested areas.⁵

All the heat generated by these objects and surfaces makes its way into the atmosphere above the city, adding supplemental heat that’s not natural.⁵

I’ve seen some tweets from a few meteorologists and other people who claim that the UHI is only or largely effective at night.

While there is some truth to that (as most of the warming seen in the U.S., for instance, is with overnight temperatures), NOAA has created maps from various U.S. cities of both high and low temperatures.⁶

The map below (Figure 5) is of the Baltimore, Maryland, 3:00 p.m. afternoon temperature on August 29, 2018.⁶

Notice how the city is noticeably warmer than its more rural surroundings, even in the afternoon. I know this from personal experience because I live in Northern Virginia, not too far from Baltimore and Washington, D.C.

Conclusion

While it’s incredible that Paris exceeded their record high on Thursday, it’s important that we look not only at trends but also give a bit of perspective.

No one should make a preconceived assumption based on one daily temperature measurement.

You have to first look at whether or not a record temperature occurred in an urban area, then see what the upper air pattern is doing, and lastly look at trends and previous years with similar atmospheric conditions.

Skeptics who use cold and snow as evidence that global warming is a hoax are always reminded by climate activists that weather and climate are vastly different—and they’d be correct.

So, why do activists blame a single record-high temperature, let alone a summer heatwave, on climate change? That I can’t answer. It seems to me that it’s “do as I say, not as I do.”

The bottom line is this: heatwaves happen, it’s summer and it’s hot.

REFERENCES

[1] Leister, Eric. “Paris breaks all-time high temperature as deadly heatwave grips Europe.” AccuWeather. July 25, 2019. Accessed July 26, 2019. https://www.accuweather.com/en/weather-news/scorching-heat-produces-all-time-record-highs-in-belgium-netherlands-as-western-europe-swelters-under-heat-wave/70008886.

[2] “Annual Maximum of Monthly Maximum of Daily Maximum Temperature.” KNMI Climate Explorer. Accessed July 26, 2019. http://climexp.knmi.nl/data/xgdcnFR000007150_max12_anom_max1_anom.dat.

[3] “Maximum Temperature PARIS/LE BOURGET.” KNMI Climate Explorer. Accessed July 26, 2019. http://climexp.knmi.nl/data/xgdcnFR000007150.dat.

[4] “Surface pressure charts.” Met Office. July 26, 2019. Accessed July 26, 2019. https://www.metoffice.gov.uk/weather/maps-and-charts/surface-pressure.

[5] “Satellites Pinpoint Drivers of Urban Heat Islands in the Northeast.” NASA. Accessed July 26, 2019. https://www.nasa.gov/topics/earth/features/heat-island-sprawl.html.

[6] Herring, David. “Citizen Scientists take to the streets to map the hottest places in ten U.S. cities.” NOAA Climate.gov. July 24, 2019. Accessed July 26, 2019. https://www.climate.gov/news-features/features/citizen-scientists-take-streets-map-hottest-places-ten-us-cities.

Soon-to-be meteorologist Chris Martz runs the website Awesome Weather Facts and regularly writes about the climate, our weather, and forecasting.